There have been numerous systems for connecting the ends of two optical fibers, with the greatest transmission efficiency usually obtained by having the tips of the two fibers abut one another. High transmission efficiency generally requires that the tips of the fibers be polished precisely flat, that the fibers be accurately aligned, and that the tips substantially abut one another with a gap everywhere along the faces of the fibers being less than one-thousandth inch. The most common approach has been to insert the pair of fiber tips into a cylindrical bore of a ferrule, and to use a spring to bias one fiber tip against the other. When a large number of fiber pairs are to be connected, a large number of springs are required to individually bias the fiber tips, resulting in a complex arrangement with many moving parts and less than high reliability. U.S. Pat. No. 5,533,157 shows a sheet of metal forming a plurality of leaf springs that each bias a separate fiber, but this still results in numerous leaf spring portions that each constitutes a moving part. A system for connecting the ends of multiple pairs of optical fibers, which enabled high efficiency transmission of light in a simple and rugged system, would be of value.
In accordance with one embodiment of the present invention, an optical fiber system is provided for efficiently connecting pairs of optical fibers, which is of a simple and rugged design. The system includes first and second housings, that each has a plurality of parallel fiber-receiving bores extending to a mating face of the housing. First and second sets of optical fibers are mounted respectively in the first and second housings, with each fiber extending through a bore and rigidly fixed in place in the bore. The mating face of each housing is polished precisely flat, and the fibers that extend through bores in that housing have tips that are polished flat and that are precisely flush with the mating face. When the two housings are brought together so their mating faces lie facewise against each other, each fiber tip is precisely aligned with a fiber tip of the other housing, and the two tips substantially abut each other, with a gap between them of less than 0.0005 inch, for high efficiency transmission of light between the two fibers.
Each fiber is fixed in place by a quantity of potting material such as epoxy. The potting material extends to the mating face and is polished flat and precisely flush with the mating face. The bores merge in a cavity at the rear of the housing, and the quantities of potting material merge into a large amount of potting material in the cavity. The first and second housings are identical, and each has a groove around the mating face, with an elastomeric seal lying in the groove. When the housings are brought together, the seals press against each other to seal the area where the mating faces engage each other.
Each housing has opposite ends with flanges, with a pair of holes in the flanges lie at opposite sides of the housing. A pair of panel screws each lies in a hole of a different flange, with the panel screws lying catercorner from each other. A pair of connecting screws for connecting the two housings, lie in holes of the second housing flanges in another catercorner arrangement.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.